Behavior of Fiber-Metal-Elastomer-Hybrid-Laminates

In Automobilen und in der Luftfahrt wurde in den letzten Jahrzehnten vermehrt auf Bauteile aus Faserverbundkunststoffen und hybriden Strukturen gesetzt. Ziel dieses Wandels waren höhere spezifische mechanische Eigenschaften, zur Gewichtsreduktion und Effizienzsteigerung. Eine Kombination von verschiedenen Materialien ermöglicht eine Struktur, die optimal zu der Belastung im Realfall passt. Eine Hybridstruktur kann durch die Kombination unterschiedlicher Materialklassen Eigenschaften erhalten, die nicht durch ein Einzelmaterial darstellbar sind. Faser-Metall-Laminate (FML) werden in der Luftfahrt eingesetzt, da sie sehr geringe Rissausbreitungsgeschwindigkeiten zulassen, was zu erhöhten Lebensdauern und größerem Leichtbaupotential führen kann. Das bekannteste FML, Glass Laminate Aluminum Reinforced Epoxy (GLARE), besteht aus Aluminiumblechen und glasfaserverstärktem Epoxidharz. Das größte Einsatzgebiet für das Laminat sind Passagierflugzeuge. Die Kombination der zwei sehr unterschiedlichen Materialien bringt die bereits genannten sehr guten dynamischen mechanischen Kennwerte. Eine Verbesserung des Leichtbaupotentials des Laminats kann durch Substitution von Glasfasern durch Kohlenstofffasern erreicht werden, da Kohlenstofffasern höhere spezifische mechanische Eigenschaften besitzen. Allerdings erfordert der Einsatz von Kohlenstofffasern in einem Hybridlaminat eine Zwischenschicht, die die verschiedenen thermischen Ausdehnungskoeffizienten abfedern und gleichzeitig die Kontaktkorrosionsneigung senken kann. Es wurde eine Elastomerzwischenschicht eingefügt und hinsichtlich des Einflusses auf die Laminateigenschaften eingehend geprüft.Die Prozessroute von GLARE im Autoklav führt zu langen Zykluszeiten, die durch eine neue Fertigungsroute drastisch reduziert werden sollten. Die neue, im Vergleich zu GLARE, kostengünstige Herstellungsroute führte zu fehlerfreien Bauteilen, wobei die Zykluszeit noch weiter reduziert wurde. Die mechanischen Eigenschaften von Faser-Metall-Elastomer-Laminaten (FMEL) wurden hinsichtlich der Eigenschaften der Einzelmaterialien ermittelt. Ein besonderer Fokus lag auf der Grenzflächenanalyse unter diversen Lasten, um denWiderstand gegen Delamination zu beschreiben. Nach einer systematischen Materialauswahl wurden quasistatische Versuche genutzt, um die mechanischen Eigenschaften des Laminats im Vergleich zu einem Faser-Metall-Laminat (FML) ohne Elastomerschicht zu zeigen und den Einfluss der Zwischenschicht auf die mechanischen Eigenschaften vergleichend zu beleuchten. Die Experimente wurden von Infrarotbildgebung, CT-Scans und Digital Image Correlation (DIC) unterstützt. Die unterstützenden Messungen wurden genutzt um Schädigungen zu detektieren und die Schädigungsentwicklung zu visualisieren, was zu einem tieferen Verständnis der Eigenschaften und Mechanismen im Laminat führen sollte. Die Eigenschaften der Einzelschichten und der Grenzflächen wurden genutzt, um das Laminatverhalten in dynamischen Experimenten vorherzusagen. Die dynamischen Versuche zeigten, dass durch die Elastomerzwischenschicht die mechanischen Eigenschaften des Laminats gesteigert werden konnten, da die duktile Zwischenschicht Delamination verhindern konnte. Die Ermüdungseigenschaften des FMEL konnten mit theoretischen Modellen validiert werden. Der Einfluss der Elastomerschicht wurde in Abhängigkeit des Versuchs beschrieben und die Eingeschaftsänderung des Laminats bewertet, um die Verbesserung des Laminats darzustellen. Die Integration der Elastomerschicht resultierte in reduzierten quasistatischen Eigenschaften, aber die dynamischen, Umwelt-, Grenzflächen- und Ermüdungseigenschaften konnten gesteigert werden

State investigative interest varies across daily life and predicts academic engagement: Replication and extension of the nomological network

Recent contributions propose to integrate a state perspective into the conceptualization of vocational interests. Such integration addresses in-the-moment expressions of interests and allows to track relations to distal outcomes of vocational interests more closely. To further the trait-state integration of vocational interests, insights into the nomological network of state vocational interests are necessary. In this preregistered experience sampling study of 217 university students, we studied state investigative interest in daily life and the relations with theory-derived person- and situation-related constructs. Results from 5631 observations across 3.5 weeks showed that specific situation characteristics, openness, happiness, and current social student role were associated with state investigative interest. Furthermore, person-aggregated state investigative interest and the reactivity of investigative interest in situations related with their academic studies predicted individuals’ overall academic engagement in some cases. Generally, the relations in the nomological network were stronger when state investigative interest and hypothesized constructs were more closely aligned. Overall, the results underline the systematic nature and psychological relevance of state vocational interests. We discuss how integrating a state perspective into research on vocational interests implies novel approaches for capitalizing on the power of vocational interests.the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation)Peer Reviewe

Treatment strategies for treatment naive HIV patients in Germany: evidence from claims data

A recent observational study of HIV patients in Germany suggests that treatment naive patients that are in a more advanced stage of their disease are more likely to receive a treatment regimen based on a boosted protease inhibitor (PI/r) compared with a non-nucleoside reverse-transcriptase-inhibitor (NNRTI) base regimen. To validate those results we analysed claims data of seven German sickness funds from 2009 to 2012 with approximately 4 million beneficiaries. Patients in a more advanced disease state (CDC class C) had a higher likelihood to receive a PI/r based regime rather than a NNRTI based regimen as their initial treatment. There was also a significant correlation between PI/r based regimen and number of comorbidities but not with age. Our results confirm a highly significant relationship between being in a more severe stage of HIV disease and a PI/r based treatment regimen

Treatment strategies for treatment naive HIV patients in Germany: evidence from claims data

A recent observational study of HIV patients in Germany suggests that treatment naive patients that are in a more advanced stage of their disease are more likely to receive a treatment regimen based on a boosted protease inhibitor (PI/r) compared with a non-nucleoside reverse-transcriptase-inhibitor (NNRTI) base regimen. To validate those results we analysed claims data of seven German sickness funds from 2009 to 2012 with approximately 4 million beneficiaries. Patients in a more advanced disease state (CDC class C) had a higher likelihood to receive a PI/r based regime rather than a NNRTI based regimen as their initial treatment. There was also a significant correlation between PI/r based regimen and number of comorbidities but not with age. Our results confirm a highly significant relationship between being in a more severe stage of HIV disease and a PI/r based treatment regimen

Estimation of Health-State Utility Values and Factors Driving Health-Related Quality of Life in People Living with HIV and AIDS and Receiving cART in Germany: Baseline Analysis of a Cohort Study

HIV has become a chronic disease since widespread of combined antiretroviral therapy (cART). Understanding the influence of therapeutic and preventive interventions on health-related quality of life (HRQoL) of people living with HIV and AIDS (PLWHA) is important. Information about health state utilities and HRQoL in PLWHA after the introduction of cART is limited, especially in Germany. The study aims to estimate and describe health state utilities and HRQoL in PLWHA in Germany and explore the effects of patient characteristics, clinical and treatment factors. Utilities and HRQoL in PLWHA in Germany were measured with the generic EQ-5D-3L questionnaire. Health state utilities were calculated based on the EQ-5D descriptive system using the German EQ-5D-3L time trade-off (TTO) value set. HRQoL was calculated based on the EQ visual analogue scale (EQ-VAS). Extensive descriptive analyses were performed to represent utility values for different groups of the patients. Generalized linear models (GLMs) with beta-inflated distributions were used to determine patient characteristics and clinical factors that influence TTO utilities and VAS scores. 1056 PLWHA completed the EQ-5D-3L questionnaires at the beginning of the study. The mean TTO utility value is 0.912 (SD ± 0.154), and the mean VAS HRQoL is 84.32 (SD ± 18.55). “Anxiety/depression” and “pain/physical discomfort” are the most affected dimensions. A longer period of living with HIV, a lower CD4-cell count, having symptomatic HIV or AIDS and an increased number of changes in therapy are associated with decreased utilities and a lower probability of having HRQoL of perfect health. No significant effect of duration of regimen was found. Depression significantly decreases TTO utility values. Higher education, full-time employment and female gender are associated with higher utilities. The resulted EQ-VAS values for PLWHA in Germany are comparable with EQ-VAS estimates for the general population. The obtained estimates can be used as inputs for health economic evaluations of HIV-interventions. Addressing anxiety and depression may reduce the quality of life impairment in PLWHA. Impact of comorbidities needs further investigation. © 2021, The Author(s)

The choice between a ritonavir-boosted protease inhibitor- and a non-nucleoside reverse transcriptase inhibitor-based regimen for initiation of antiretroviral treatment - results from an observational study in Germany

Background: This study aims at identifying predictors of the treatment decision of German physicians with regard to a non-nucleoside reverse transcriptase inhibitor (NNRTI) or a ritonavir-boosted protease inhibitor (PI/r) -based initial treatment regimen. Methods: The study is based on a sub analysis of a nation-wide multi-centre, non-interventional, prospective cohort study. 133 patients were identified, who received antiretroviral first-line therapy. By means of a logistic regression, factors that determine the treatment strategy for treatment-naïve patients were analysed. Results: Compared to patients receiving a NNRTI-based initial regimen, patients treated with PI/r are slightly younger, less educated, in a later stage of HIV and have more concomitant diseases. Regression analysis revealed that being in a later stage of HIV (CDC-C) is significantly associated with a PI/r-based treatment decision. Conclusions: Our analysis is the first study in Germany investigating sociodemographic and disease-specific parameters associated with a NNRTI- or a PI/r-based initial treatment decision. The results confirm that the treatment decision for a PI/r strategy is associated with disease severity

Wüchsigkeit und physiologische Aktivität der Rebe in Abhängigkeit von verschiedenen weinbaulichen Bewirtschaftungssystemen

Based on a field trial, the impact of three different viticultural management strategies on vigour and grapevine physiology of Vitis vinifera cv. Riesling was compared. The vines were planted in 1991 at Geisenheim (Rheingau, Germany) and three different management strategies i.e. integrated (code of good practice), organic (European Union Regulation 834/07 and ECOVIN standard) and biodynamic (European Union Regulation 834/07 and DEMETER standard) were established in 2006. Even though all treatments received the same level of nutrients and water a decline in vigour, expressed as lateral growth, was observed for the organic and biodynamic treatment during three seasons (2010 to 2012). During dryer conditions (2011) a reduction of physiological activity expressed as stomatal conductance gs, assimilation rate A and transpiration E two weeks after full-bloom and a reduction in pre-dawn water potential at veraison were assessed for the biological treatments. In 2012 under wetter growing conditions neither differences in physiological activity nor in pre-dawn water potential were observed. Therefore changes in physiological activity and pre-dawn water potential are just partially responsible for the reduced vigour in the biological treatments